Transcript for Alleged Violent Sex Offender on the Loose and on US Soil

So why isn't there a warrant for his arrest. Abc's neil karlinsky has the latest. Reporter: Tonight canadian police say 48-year-old michael sean stanley is here in the u.S. But can't be arrested even though authorities want him behind bars. Specifically we have no authority to get him. Reporter: He has a long history of sexual offenses against women and children in canada. BUT OCTOBER 1st, HE CUT OFF THE Electronic bracelet used to monitor him and took off, frightening enough to put schools on lockdown near edmonton, alberta. We have an emergency plan, we have enacted it. Reporter: Amazingly u.S. Officials say the canadians didn't file the necessary paperwork to have him held at the border. He was able to legally cross into washington state from vancouver. And because there was no warrant for him in the u.S., He's free to stay. This individual poses a significant public safety risk. One of the most significant breakdowns appears to be the failure of the canadian authorities to alert the united states. Reporter: Canadian police say they know where he is. But u.S. Officials say the information hasn't been shared with them. And canada's process of getting a warrant could take months. Leaving this dangerous sex offender free on the streets of the u.S. For now. Neil karlinsky, abc news, seattle.

This transcript has been automatically generated and may not be 100% accurate.

Now Playing: Deadly terror attack on streets of Barcelona

Now Playing: Two people in custody in connection with Barcelona attack

Now Playing: Trump rails against the removal of 'beautiful statues'

Now Playing: Millions of people on severe weather alerts from Michigan to Pennsylvania

{"id":20549692,"title":"Alleged Violent Sex Offender on the Loose and on US Soil","duration":"1:30","description":"Michael Sean Stanley is on the loose in the U.S. because he can't be arrested.","url":"/WNT/video/alleged-violent-sex-offender-loose-us-soil-20549692","section":"WNT","mediaType":"default"}